Amit Singhal, an Influential Engineer at Google, Will Retire

SAN FRANCISCO — Alphabet, the parent of Google, is losing one of its most influential engineers, but his successor’s background is indicative of how important artificial intelligence technology is becoming to the Silicon Valley company.

Amit Singhal, the company’s senior vice president for search, and one of the earliest builders of its global computer system, announced that he would retire on Feb. 26. He has been involved with many of the technologies that have made Alphabet an engineering powerhouse and one of the world’s most valuable companies.

His replacement, John Giannandrea, currently works in artificial intelligence, or A.I., at Alphabet. A.I. has been increasingly important to Google and other companies like Amazon, as they seek to build products that can do things like respond to voice commands, deliver complex alerts about changes to a user’s schedule, or drive a car.

In a post to the Google Plus social network, Mr. Singhal indicated that he wished to spend time with his family and intended to give away some of his fortune. “It has always been a priority for me to give back to people who are less fortunate, and make time for my family,” he wrote.

Mr. Singhal, 48, joined Google in 2000 as employee No. 176. A native of India, he has a doctorate in computer science from Cornell and worked at AT&T Labs before Google. One of his earliest jobs at Google was rewriting the initial breakthrough algorithms developed by Google’s co-founders, Larry Page and Sergey Brin.

Google was one of many search engines, but it distinguished itself both in the quality of its results and in building features like spell check, which could offer correct answers to misspelled queries. The early engineering team also developed search-related tools for its advertising, which quickly turned into a very profitable business.

Unlike some other early Google employees who scaled back their efforts or left the company altogether, Mr. Singhal appeared to remain fully engaged in advancing search. In an interview last summer, he described his job as looking at “what’s beyond the horizon,” particularly in building ways that people can easily get information from mobile devices.

On Monday, Alphabet, now the parent company of Google, announced that its revenue in the last three months of 2015 was $21.3 billion, and operating income was $5.4 billion — both significant increases from the same period a year earlier.

Alphabet hopes to draw on skills developed by Mr. Singhal and Mr. Giannandrea to build things like self-driving cars. Last week, a company purchased by Alphabet, called DeepMind, announced that its computers had defeated a high-ranking champion at Go, a game considered more complex than chess.

Mr. Giannandrea, 50, came to Google from the 2010 acquisition of another company, Metaweb Technologies. He has played an important role in incorporating machine learning into various Google products, like the image recognition in Google Photos and smart replies in Gmail’s Inbox.

In addition to Mr. Singhal’s stated philanthropic and family interests, it is likely that his skills in building large computer networks and in A.I. will still be in demand.

A version of this article appears in print on , on Page B8 of the New York edition with the headline: A Top Engineer for Search Is Set to Exit Google. Order Reprints | Today’s Paper | Subscribe